it is common experience to associte chemial reaction with equilibrium constant greater than one with the evolution of heat, in other words, with negative H values. there are, in fact, many striking examples . formation of ch3cl and hcl from ch4 and chl2 has a K of 10 and H of -24 kcal per mole of ch3cl formed at 25. combustion of hydrogen with oxygen to give water has a K of 10 and H =-57 kcal per mole of water formed at 25. however this correlation between K and H is neither universal nor rigorous. rection are know that absorb heat ( are endothermic ) and yet have K>1 .other reactions have large H valus and equilibrium constant much less than 1
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